The present invention relates to a method to connect a wide size document scanner to a laser printer engine for copying with size reduction.
It is a more particular method to connect a wide scanner such as a flip chart copier (FCC) to laser printer engines including digital copiers. The flip chart copier scans a flip chart (27".times.34") and prints letter size (8.5".times.11") outputs. The scanning resolution of an FCC is typically 1.176 dots/mm and the printing resolution of the thermal printer is 4 dots/mm.
There are other approaches similar to a flip chart copier (FCC), such as available from Contex A/S of Denmark. In these products, the original sizes of A0 through A3 size paper can be copied to A4 size thermal paper.
There are some copiers which can automatically adjust the magnification to match the original to the copy, such as disclosed in Ikesue et al U.S. Pat. No. 4,277,163. The problem of this approach is that because of the analog process, the data cannot be transferred to other equipment. For example, with wide scanners developed by other vendors, the plotter developer has less control of the optical system. Therefore, the data must be manipulated digitally in order to be plotted.
Kamon U.S. Pat. No. 4,327,433 describes magnification change of image data. The approach in Kamon can control the magnification and reduction in 1% steps. Kamon's method can work in an application when the developer has control over the scanner. In addition, Kamon's method does not require controlling the clock rate or pulse width of the plotter.
However, there are two problems associated with the above approach. First, the FCC was developed with a simple digitization process of scanner. Therefore, if a laser printer needs to interface with the FCC, binary data are already developed by the FCC, leaving no possibility of applying Kamon's method.
Another problem is the cost. Kamon's method requires additional cost over the simple binarization employed by FCC. If the cost is not an issue, the FCC can incorporate Kamon's method. The current digital copiers require multiple scans when multiple copies are requested, even though it is feasible to store the image in the memory.
The control of the pulse width to manipulate the resolution of a laser printer is well known. For example, by doubling the clock width, the horizontal resolution of a 300 DPI printer can be changed into 600 DPI. This type of application was developed to increase the image quality by doubling the addressibility of pixels. Miyagi U.S. Pat. No. 4,819,066 also used a pulse width modulation to increase the quality of gray scale by changing the pixel pulse width. None of these applications were, however, aimed at using pulse width to adjust image size obtained by the different system.
Parisi U.S. Pat. No. 4,807,156 describes adjustable print size by controlling a polygon clock and pixel clock. The method described by Parisi is not available to most of laser printer controller developers who are not the maker of laser printer makers.